code: def test_windbarbs_color_warning(self):
      x = np.linspace(-1, 1, 4)
      X, Y = np.meshgrid(x, x)
      U, V = 10 * X, 7 * Y
  
      angle = np.pi / 2 - np.arctan2(-V, -U)
      mag = np.hypot(U, V)
  
      barbs = gv.WindBarbs((X, Y, angle, mag)).opts(
          colorbar=True,
          clim=(0, 50),
          color="Magnitude",
          flagcolor="black",
          barbcolor="black",
      )
      with ParamLogStream() as log:
          mpl_renderer.get_plot(barbs)
      log_msg = log.stream.read()
      warning = (
          "Cannot declare style mapping for 'color' option and either "
          "'flagcolor' and 'barbcolor'; ignoring 'flagcolor' and 'barbcolor'.\n"
      )
      self.assertEqual(log_msg, warning)
  
file_path: geoviews/geoviews/tests/plotting/mpl/test_chart.py
imports: import numpy
  import xarray
  import geoviews
  from geoviews.element import WindBarbs
  from holoviews.tests.plotting.utils import ParamLogStream
  from geoviews import Store
  from test_plot import TestMPLPlot
label_desc: Use image node_id 9 for calling the TestWindBarbsPlot obj's underlying member method code with example usage: obj.test_windbarbs_color_warning() without return types